Microbial dysbiosis of the vaginal microbiome and its association with infectious pregnancy complications

Background: The vaginal microbiome is vital for the health of the female reproductive tract. Evidence has existed that depletion of named Lactobacilli species and escalation in anaerobic pathogens may give rise to pregnancy complications. Objectives: The aim of this study was to compare the vaginal microbiome in pregnant women with and without adverse outcome of their pregnancies, and its potential use as a prenatal screening test. Methods: A case– control study was conducted on 60 pregnant women between age of 20–39 years and were classified into two groups; I, normal pregnancy groups with infected (30 cases) and II complicated ones (30 cases), including preterm labour, bacterial vaginosis and threatened miscarriage. Vaginal cultures were taken during the second trimester by way of swab sample and cultured using routine aerobic-anaerobic methods. Colony counts of Lactobacillus spp. and pathogenic bowels (eg, Gardnerella, Mobiluncus, Bacteroides) cultured and statistics calculated. Results: Women with normal pregnancies exhibited significantly higher Lactobacillus levels (8.0 ± 1.0 log10 CFU/mL) compared to those with complications (4.0 ± 1.2 log10 CFU/mL, p < 0.001). In contrast, pathogenic anaerobes were markedly increased in the complications group (6.5 ± 1.1 log10 CFU/mL vs. 2.0 ± 0.8 log10 CFU/mL, p < 0.001). Microbiomes dysbiosis was highly correlated to adverse pregnancy outcomes, such as preterm labor and miscarriage. Conclusions: Shift in the vaginal microbiome, particularly reduction of protective Lactobacillus spp. and yeast) and overgrowth of anaerobic organisms are strongly associated with complications during pregnancy. These data indicate potential value of microbiome profiling as an early marker, and a strong case for preventive measures including probiotics.